Startup Idea : Organising Events with Friends

The hardest part of organising a catchup with friends or acquaintances is finding the best day/night that everyone is free. I think we've all experienced the pain of countless back and forth emails until a time is found or everyone gives up. Facebook has their events option but what about createing a calendar as well so your friends can select what day and time is best for them. This way you can instantly see what the best option would be. You could also then have a suggestion section of what is available to do in the area. Ie, restaurant, movies, etc. Payments options can be included if an event needs to be paid for before it occurs. Many options possible but this would be the basic idea.